Drupal for audio transcription?

Hi,

I am trying to make an audio transcription website, where users can upload audio (spoken word), have it transcribed (to text) by someone else, and then download the resulting text in a number of formats.

Using Workflow module with these states: Uploaded, Processing, Checking, Ready, Downloaded.
I have the following roles: client, transcriber, administrator, I've set up appropriate "transitions" and tested the Workflow using an Audio node (Audio module).

I have also created a custom content type (AudioJob) that uses a CCK Audio field so I can support multiple audio files in one Audio transcription "Job". This content type also includes a computed field that counts the VBC (number of visual black characters) in the Body field (where the transcribed text goes).

I would also like to incorporate E-commerce, and use the invoicing facility in the future, but this is not as important as getting a working "service" up and running.

I have a bunch of questions for anybody kind enough to help (where they can) ...

Has anyone tried this kind of thing before? Do you have any advice?

Does this sound like the "right approach", or more like grief?

How do I provide a simple node creation process? Is FormFilter the only option?

How do I provide a form where a transcriber can listen to the Audio AND edit the Body node at the same time?

How would I go about integrating the SpellCheck and AutoSave for the Body node?

How do I produce a formatted and downloadable file from a node field (Body text) in PDF (or other) formats?

Please help if you can ... I am a little lost with the "practical application" of all these great Drupal modules!